I have been a Novak Djokovic fan long before his rise to supremacy. As a dedicated tennis fan, I admire the enthusiasm and level of play he has brought to the sport. As an expert in gluten-related disorders, I am grateful for the awareness he has raised about the gluten-free lifestyle.

When I heard about his new book, Serve to Win: The 14-Day Gluten-Free Plan for Physical and Mental Excellence, I was both intrigued and anxious. I wanted to hear Djokovic’s personal story, but with so much confusion surrounding the gluten-free diet, I had to question whether he could deliver sound nutrition advice.

Djokovic sprinkles good tips and advice throughout Serve to Win, including promoting cooking at home using high-quality ingredients, eating slowly and consciously focusing on quality over quantity, and a holistic approach to health that includes meditation and getting adequate sleep. And I have to give kudos to his list of favorite gluten-free foods and the meal plans and recipes he shares (contributed by Candice Kumai).

Why Djokovic's book stumbles

However, readers are drawn to the book title, which specifically focuses on the gluten-free diet for achieving peak physical and mental performance. This is where Djokovic falters. Serve to Win has too many inconsistencies, inaccuracies, and statements not supported by scientific literature, thereby adding to consumers’ confusion about the gluten-free diet.

I’m concerned by Djokovic’s interchangeable use of the terms wheat-free, gluten-free and grain-free, because these terms are not synonymous. In some parts of the book he talks about the benefits of eliminating all grains, specifically saying that more grains means more health issues, including obesity, diabetes and heart problems. But then he also shares the list of gluten-free grains that he does eat (as he should); considerable evidence shows a relationship between whole grains and a reduced risk of these diseases.

Several statements in the book are either not supported by scientific literature or are downright inaccurate. For example, when writing about the gluten-free diet, it is not okay to refer to celiac disease as a gluten allergy when it is an autoimmune disorder—something quite different.

Djokovic states that eliminating gluten can lead to rapid weight loss for the general population. However, leading authorities on gluten-related disorders will tell you that evidence does not show that removing gluten from the diet in and of itself is effective for weight loss. I’m disappointed that Serve to Win fosters the confusion on this much discussed matter.

The biggest issue I have with this book is that its overall message implies that the general population—those who don’t have celiac disease, gluten sensitivity or another condition in which the gluten-free diet can alleviate symptoms—will benefit from removing gluten from their diet. Right now, there just isn’t any evidence to show that this is the case.

What's worth heeding, what's not?

Here are my 5 takeaway points from Serve to Win:

1. The Good Food Guide in the appendix is an excellent list of nutritious foods to make a part of your regular diet, whether or not you choose to eat gluten-free.

2. The recipes are nutritious and easy to make. I recommend including them in your cooking repertoire.

3. Use the daily meal plans as a guide, noting that, unless you are training eight hours a day like Djokovic, you’ll have to eat far less calories.

4. Invest in a holistic approach to healthful living that includes regular physical activity, adequate sleep, mindfulness, and stress management techniques.

5. Know that while people with celiac disease, gluten sensitivity and even some with other autoimmune disorders benefit from a gluten free diet, there is no evidence to show that the general population will either be healthier or lose weight simply by removing gluten from the diet.